7 STW Process DemonstrationPilot Program ResultsOutlet Arsenic Concentration, µg/l20AA pH = 7.5S33 1 pH = 6.5AA pH = 6.5S33 2 pH = 7.515S33 1 pH = 7.5105This graph depicts the results from some of the pilot test runs. Activated alumina had an early breakthrough at about 20,000 bed volumes, a term used to measure the treatment ratio of water to media. Even though the alumina can be regenerated, it loses over 10% of its capacity in subsequent adsorption cycles.The granular ferric hydroxide performed extremely well with no breakthrough detected after over 170,000 bed volumes treated. The influent As concentration was 20 g/L.50,000100,000150,000200,000250,000Bed Volumes TreatedColumn Size - 4”-Ø •Contact Time- 3 Min EBCT for GFH; 6 Min for AACurrent Bayoxide® E33 Pilot Superimposed

12 SavagePlate™ Media Retention Plate & SupportSORB 33™ SystemProcess Flow DiagramBayoxide E33™ArsenicAdsorbentDistribution TroughsSavagePlate™ Media Retention Plate & SupportMedia FillSightGlassMediaDrainAir Scour(Future)ManwayRaw WaterWash WaterClean WaterInletOutletFICpHIBackwashB’wash Efflu’tForwardFlushPDIDip Tube& VentTo Disinfection &DistributionFrom Well PumpTo Sewer or PondPIFQIVacuumBreakerPressureReliefSiteglassSpent MediaVirgin MediaFrom TruckTo Dumpster/TruckEductorMotive WaterService byST ServicesSevern Trent Services, working with ST Water, has brought the developed SORB 33™ technology to the U.S. Systems have been designed for single train capacities of 0.3 to 1.6 MGD. The systems employ the Bayoxide® E33 media supported on Severn Trent Services’ proprietary b plate™. This diagram is available in our SORB 33™ brochure.The depicted system is sufficient for most installations, but options are available for pH adjustment, backwash water pumping and residual water storage. Media removal and replacement is provided as a service through Severn Trent Services.

13 Il primo sistema SORB 33 Nottingham, U.K. STW As Removal PlantThis photo shows the 5 train As adsorber system at the Nottingham plant. Each vessel is 11 Ft in diameter and can hold 10 m3 or 5.4 tons of media. The plant was commissioned in early 1999.Since then, Severn Trent Water has built nearly half of the SORB 33™ systems required for their other 17 well water sites.Nottingham, U.K.Capacità m3/giornoCinque Filtri da 3,3 m ØAvviamento - Genn. ‘99STW As Removal Plant

17 Riempimento dei FiltriStudiate varie possibilitàDirettamente da big bags da 500 kgTramite eiettoreDa autobotteInitially, costs dictated that a flat bed truck and rig was the way that the media would be delivered. However, this method was time consuming and labour intensive. Severn Trent Water ltd subsidiary Company, Grafham Carbons had a tanker that was coming off line and offered a delivery service with this dedicated tanker. Trials have been successful cutting down delivery time to under 2 hours for 8 cu m and reducing labour. The tanket has been painted "orange" to reduce the appearance of staining from spilt media

21 Perparazione del ProdottoBayoxide E 33 può contenere fini che devono esse rimossi prima della messa in servizioControlavaggio lento durante il riempimentoControlavaggio per 10 volumi di lettoRisciacquo in direzione flusso per 5 volumi di lettoProdotto pronto per il servizioImportant to have a slow upwash during delivery to remove fine solids which it is thought, can get trapped and require extended conditioningwash to remove. A conditioing wash at 30 m/h has been found the most effective to clean up the bed followed by a forward rinse at the prevailing flow of the works. Latest data from Hilton shows that the water is cleaned up within 1 BV and ready to go into supply. We currently undertake bacteriological testing before putting into service but we are now getting sufficient data to allow beds to go straight in without waiting for these results

22 Sedimentazione dei FiniI solidi (fini) dall’operazione di condizionamento non sedimentano facilmente24 Ore per sedimentareI solidi dal controlavaggio sedimentano più velocemente<<24 oreTrials have shown that desin settlement time for conditioning washings can be reduced from 48 hours to 24 hours and for service washes, less than 24 hours. Further work is to be undertaken on this subject

23 Smaltimento del ProdottoAspirazione del prodottoTramite eiettoreMetodo utilizzato inizialmenteProduce molto effluente a scaricoAspirazione da autobotte (con pompa a vuoto)Metodo migliorePoca acqua richiestaTempi brevi di fermataProdotto smaltito in discaricaIl prodotto passa il test dell’eluato (TCLP)A high vacuum tanker has successfully removed the media from one adsorber vessel at Burton Joyce without the need to add any water. However, because of the adsorber design used, it was necessary to enter the vessel to "vac" out the remnants of the media - this necessitated a full disinfection with extends down time. In terms of time, no water, ease of tipping, this method is favoured over a tanker equipped with an eductor

24 Bayoxide E33 Chaddesley CorbettUnitsDryWeightBayoxide E33 Chaddesley CorbettVessel 108/12/03Bamg/kg127As4633Al283Ti45Ag0.3Total - P% DW0.06Co23Fe516349Cd8-Cr78Cu191Pb18Ni54Zn52Mn1388V58A high vacuum tanker has successfully removed the media from one adsorber vessel at Burton Joyce without the need to add any water. However, because of the adsorber design used, it was necessary to enter the vessel to "vac" out the remnants of the media - this necessitated a full disinfection with extends down time. In terms of time, no water, ease of tipping, this method is favoured over a tanker equipped with an eductor

28 Impianti in Attività in UKSitoMl/giornoN° FiltriAstley18,05August Hill5,53Beckbury6,7Bellington14,04Burton Joyce (Nottingham)20,0Chaddesley Corbett7,0Copley6,8HattonHilton22,86Lee Brockhurst15,2Markham ClintonRuyton XI Towns7,3Shugborough4,52SugarbrookWellesbourne4,0Westwood11,6Chaddesley Corbett operating since Nov no arsenic breakthrough noted. Two vessels in operation since May 2002 with all flow going through the vessels - the residents of the surrounding area including Kidderminster are the first to receive water with complete removal of arsenicBurton Joyce has been off line while phosphate dosing kit is installed - it will be re-commissioned soonHilton - first adsorber filled 17th Sept 2002All other sites to be filled on a staggered basis completed by Oct 2003

32 Impianti in Attività in USASiteWater Company / Area / StateCountryChandlerArizonaUSADare CountyNorth CarolinaEl PasoTexasGardiner ParkMontanaMantecaCaliforniaMesaRio RanchoNew MexicoSacramento CityScottsdaleChaddesley Corbett operating since Nov no arsenic breakthrough noted. Two vessels in operation since May 2002 with all flow going through the vessels - the residents of the surrounding area including Kidderminster are the first to receive water with complete removal of arsenicBurton Joyce has been off line while phosphate dosing kit is installed - it will be re-commissioned soonHilton - first adsorber filled 17th Sept 2002All other sites to be filled on a staggered basis completed by Oct 2003